diff --git a/gum/gumspinlock.h b/gum/gumspinlock.h
index c0874c779..ba4c47e7c 100644
--- a/gum/gumspinlock.h
+++ b/gum/gumspinlock.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2010-2019 Ole André Vadla Ravnås <oleavr@nowsecure.com>
+ * Copyright (C) 2010-2024 Ole André Vadla Ravnås <oleavr@nowsecure.com>
  * Copyright (C) 2024 Francesco Tamagni <mrmacete@protonmail.ch>
  *
  * Licence: wxWindows Library Licence, Version 3.1
@@ -8,7 +8,7 @@
 #ifndef __GUM_SPINLOCK_H__
 #define __GUM_SPINLOCK_H__
 
-#include <glib.h>
+#include <gum/gumdefs.h>
 
 #define GUM_SPINLOCK_INIT { NULL }
 
@@ -21,11 +21,11 @@ struct _GumSpinlock
   gpointer data;
 };
 
-void gum_spinlock_init (GumSpinlock * spinlock);
+GUM_API void gum_spinlock_init (GumSpinlock * spinlock);
 
-void gum_spinlock_acquire (GumSpinlock * spinlock);
-gboolean gum_spinlock_try_acquire (GumSpinlock * spinlock);
-void gum_spinlock_release (GumSpinlock * spinlock);
+GUM_API void gum_spinlock_acquire (GumSpinlock * spinlock);
+GUM_API gboolean gum_spinlock_try_acquire (GumSpinlock * spinlock);
+GUM_API void gum_spinlock_release (GumSpinlock * spinlock);
 
 G_END_DECLS